Stille Nacht...

The Sainsbury's Christmas advert is based on the story of how soldiers from both sides in World War I at Christmas time declared an unofficial truce and met in no-man's-land to exchange greetings and even to play a football match.  Gives you a good warm glow doesn't it?  So it might come as a bit of a shock to find that this was looked on with something like horror by the high commands of both sides. The idea of any sort of fraternisation with the enemy was seen in the official mind as somewhat akin to treason, and orders went out that there was to be no repeat of this type of behaviour.  Somewhat diminishes that good warm glow, doesn't it?